Ambrosia artemisiifolia L. is annual invasive plant from Asteraceae family. Because of its competitive abilities it can cause significant direct damage in yield loss and indirect damage by producing allergenic pollen. As a result, common ragweed is listed as the most important agricultural weed of today. As monocarpic species it reproduces only by seeds which are dormant and these seeds can persist for tens of years in the soil seed bank. Seed can be dormant, dead or alive. To determine condition of the seeds we tested them through two experiments: germination test on a filter paper with seed taken from plants and second germination test on quartz sand with seed from the soil seed bank. It is also used TTC, or triphenyltetrazolium chloride test which is used to detect cellular respiration in parts of the tissue. Our aim was to determine viability of the seeds. After laboratory research it is established that viability of common ragweed decreases with age.